.btn-group
  button.btn.btn-default.smqtk-iqr-annotate.smqtk-iqr-positive(class=(positive ? 'selected' : ''))
    | Pos
  button.btn.btn-default.smqtk-iqr-annotate.smqtk-iqr-negative(class=(negative ? 'selected' : ''))
    | Neg
